The most ambitious project to study one of nature’s most complex pieces of the machinery—the human brain—is now in danger of dissolution.

Last year, the European Commission (EC) launched the $2.7 billion Human Brain Project in the hopes of translating advanced neuroscience research into a supercomputer simulation of the brain. Scientists have been circumspect about its mission from the outset, claiming that a large-scale simulation is premature: despite the influx of new research, we still don’t know enough about the brain to put together a complex and accurate model. Today, 130 of those concerned scientists from across the globe expressed their frustrations in an open letter to the EC.

Researchers from across the globe have threatened to boycott the Human Brain Project, saying that its aims are premature. Here, an MRI provides detail of the connections in the brain.

Central to the latest controversy are recent changes made by Henry Markram, head of the Human Brain Project at the Swiss Federal Institute for Technology in Lausanne. The changes sidelined cognitive scientists who study high-level brain functions, such as thought and behaviour. Without them, the brain simulation will be built from the bottom up, drawing on more fundamental science, such as studies of individual neurons. The brain, the most complex object known, has some 86bn neurons and 100tn connections.

“The main apparent goal of building the capacity to construct a larger-scale simulation of the human brain is radically premature,” Peter Dayan, director of the computational neuroscience unit at UCL, told the Guardian.

“We are left with a project that can’t but fail from a scientific perspective. It is a waste of money, it will suck out funds from valuable neuroscience research, and would leave the public, who fund this work, justifiably upset,” he said.

The gravity of the situation is such that any further action on part of the EC could trigger a boycott, disrupting neuroscience research altogether. And if researchers agree to what they say are unrealistic goals, they risk severe funding problems in the future if those goals aren’t met.

Still, many scientists acknowledge the project’s importance and note that it could make a positive impact on the field if reconfigured to fit more scientists’ needs. The EC, some say, merely wants to create new tools to make sense of the existing information we have.

Regardless, the outcome of this controversy could affect President Obama’s BRAIN Initiative, which has similar goals and was originally inspired by the Human Brain Project, as well as peripheral projects like BigBrain.